Chloroindium phthalocyanine is useful as a charge carrier generating pigment in electrophotographic photoreceptors. Chloroindium phthalocyanine is characterized by long wavelength infrared absorption at about 780 nm. Hence, chloroindium phthalocyanine crystals and halogenindium phthalocyanine crystals in general are candidates for use as charge generating pigments in photoreceptors that are used in printers having 780 nm laser diode exposure systems. However, photoreceptors that contain generating layers with chloroindium phthalocyanine are characterized by low sensitivity.
U.S. Pat. No. 4,471,039 to Borsenberger et al., teaches photoconductive elements containing the .beta.-phase form of an indium phthalocyanine. U.S. Pat. No. 4,555,463 to Hor et al. teaches a photoresponsive imaging member comprised of a chloroindium phthalocyanine photogenerating composition. U.S. Pat. No. 4,587,188 to Kato et al. and U.S. Pat. No. 4,731,312 to Karo et al. teach a photoconductor with a chloroindium phthalocyanine and a method for electrophotography with a light source having a wavelength of about 650 nm or greater.
U.S. Pat. No. 5,302,710 to Nukada et al. teaches a phthalocyanine mixed crystal comprising a halogenated indium phthalocyanine and a halogenated gallium phthalocyanine. Nukada et al. discloses an electrophotographic photoreceptor containing the phthalocyanine mixed crystal. The mixed crystal is prepared by dry milling and treatment with an organic solvent. Electrophotographic photoreceptors containing the mixed crystal are characterized by improved stability upon repeated use.
Loutfy et al., "Near-Infrared Photoreceptor Devices Incorporating Chloroindium Phthalocyanine," Journal of Imaging Science, Volume 29, No. 4, July/August 1985, pp. 148-153 teaches the synthesis and purification of organic photoconductor chloroindium phthalocyanine. Loutfy et al. teaches the determination of X-ray diffraction characteristics of crystals of the choloroindium phthalocyanine and xerographic measurements of photoreceptor compositions containing chloroindium phthalocyanine. The disclosure of this reference is incorporated herein by reference.
The present invention relates to halogenindium phthalocyanines that are characterized by improved sensitivity. The improved sensitivity enables the halogenindium phthalocyanine to be used in high speed printers.